Sustained drug release from surface modified UHMWPE for acetabular cup lining in total hip implant

Sonochemical Deposition of Gentamicin Nanoparticles at the PCV Tracheostomy Tube Surface Limiting Bacterial Biofilm Formation

BACKGROUND

The use of nanotechnology in the production of medical equipment has opened new possibilities to fight bacterial biofilm developing on their surfaces, which can cause infectious complications. In this study, we decided to use gentamicin nanoparticles. An ultrasonic technique was used for their synthesis and immediate deposition onto the surface of tracheostomy tubes, and their effect on bacterial biofilm formation was evaluated.

METHODS

Polyvinyl chloride was functionalized using oxygen plasma followed by sonochemical formation and the embedment of gentamicin nanoparticles. The resulting surfaces were characterized with the use of AFM, WCA, NTA, FTIR and evaluated for cytotoxicity with the use of A549 cell line and for bacterial adhesion using reference strains of S. aureus (ATCC^® 25923™) and E. coli (ATCC^® 25922™).

RESULTS

The use of gentamicin nanoparticles significantly reduced the adhesion of bacterial colonies on the surface of the tracheostomy tube for S. aureus from 6 × 10⁵ CFU/mL to 5 × 10³ CFU/mL and for E. coli from 1.655 × 10⁵ CFU/mL to 2 × 10¹ CFU/mL, and the functionalized surfaces did not show a cytotoxic effect on A549 cells (ATTC CCL 185).

CONCLUSIONS

The use of gentamicin nanoparticles on the polyvinyl chloride surface may be an additional supporting method for patients after tracheostomy in order to prevent the colonization of the biomaterial by potentially pathogenic microorganisms.

Surface Engineering Strategies to Enhance the In Situ Performance of Medical Devices Including Atomic Scale Engineering

Decades of intense scientific research investigations clearly suggest that only a subset of a large number of metals, ceramics, polymers, composites, and nanomaterials are suitable as biomaterials for a growing number of biomedical devices and biomedical uses. However, biomaterials are prone to microbial infection due to Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis), hepatitis, tuberculosis, human immunodeficiency virus (HIV), and many more. Hence, a range of surface engineering strategies are devised in order to achieve desired biocompatibility and antimicrobial performance in situ. Surface engineering strategies are a group of techniques that alter or modify the surface properties of the material in order to obtain a product with desired functionalities. There are two categories of surface engineering methods: conventional surface engineering methods (such as coating, bioactive coating, plasma spray coating, hydrothermal, lithography, shot peening, and electrophoretic deposition) and emerging surface engineering methods (laser treatment, robot laser treatment, electrospinning, electrospray, additive manufacturing, and radio frequency magnetron sputtering technique). Atomic-scale engineering, such as chemical vapor deposition, atomic layer etching, plasma immersion ion deposition, and atomic layer deposition, is a subsection of emerging technology that has demonstrated improved control and flexibility at finer length scales than compared to the conventional methods. With the advancements in technologies and the demand for even better control of biomaterial surfaces, research efforts in recent years are aimed at the atomic scale and molecular scale while incorporating functional agents in order to elicit optimal in situ performance. The functional agents include synthetic materials (monolithic ZnO, quaternary ammonium salts, silver nano-clusters, titanium dioxide, and graphene) and natural materials (chitosan, totarol, botanical extracts, and nisin). This review highlights the various strategies of surface engineering of biomaterial including their functional mechanism, applications, and shortcomings. Additionally, this review article emphasizes atomic scale engineering of biomaterials for fabricating antimicrobial biomaterials and explores their challenges.

[Research progress on antibacterial properties of porous medical implant materials]

OBJECTIVE

The antibacterial properties of porous medical implant materials were reviewed to provide guidance for further improvement of new medical implant materials.

METHODS

The literature related to the antibacterial properties of porous medical implant materials in recent years was consulted, and the classification, characteristics and applications, and antibacterial methods of porous medical implant materials were reviewed.

RESULTS

Porous medical implant materials can be classified according to surface pore size, preparation process, degree of degradation in vivo, and material source. It is widely used in the medical field due to its good biocompatibility and biomechanical properties. Nevertheless, the antibacterial properties of porous medical implant materials themselves are not obvious, and their antibacterial properties need to be improved through structural modification, overall modification, and coating modification.

CONCLUSION

At present, coating modification as the mainstream modification method for improving the antibacterial properties of porous medical materials is still a research hotspot. The introduction of new antibacterial substances provides a new perspective for the development of new coated porous medical implant materials, so that the porous medical implant materials have a more reliable antibacterial effect while taking into account biocompatibility.

Alendronate Release from UHMWPE-Based Biomaterials in Relation to Particle Size of the GUR Powder for Manufacturing

Ultra-high molecular weight polyethylene (UHMWPE) is widely used in endoprosthetics and has been the subject of countless studies. This project investigates the dependence of alendronate (AL) release on the molecular weight of the UHMWPE used (GUR1020 and GUR1050). A 0.5 wt% AL was added to the UHMWPE during the production of the moldings. In addition to the 14-day release tests, biocompatibility tests such as live dead assay, cell proliferation assay (WST) and Lactate dehydrogenase test (LDH) with MG-63 cells as well as a tensile test according to DIN EN ISO 527 were carried out. The released AL concentration was determined by HPLC. A continuous release of the AL was observed over the entire period of 2 weeks. In addition, a correlation between molar mass and AL release was demonstrated. The GUR1020 showed a release four times higher than the GUR1050. Both materials have no negative influence on the proliferation of MG-63 cells. This was also confirmed in the live/dead assay by the increase in cell count. No cytotoxicity was detected in the LDH test. The addition of 0.5 wt% AL increased the elongation at break for GUR1020 by 23% and for GUR1050 by 49%. It was demonstrated that the choice of UHMWPE has an influence on the release of AL. The particle size in particular has a strong influence on the release behavior.

The Role of Nanomechanics in Healthcare

Nanomechanics has played a vital role in pushing our capability to detect, probe, and manipulate the biological species, such as proteins, cells, and tissues, paving way to a deeper knowledge and superior strategies for healthcare. Nanomechanical characterization techniques, such as atomic force microscopy, nanoindentation, nanotribology, optical tweezers, and other hybrid techniques have been utilized to understand the mechanics and kinetics of biospecies. Investigation of the mechanics of cells and tissues has provided critical information about mechanical characteristics of host body environments. This information has been utilized for developing biomimetic materials and structures for tissue engineering and artificial implants. This review summarizes nanomechanical characterization techniques and their potential applications in healthcare research. The principles and examples of label-free detection of cancers and myocardial infarction by nanomechanical cantilevers are discussed. The vital importance of nanomechanics in regenerative medicine is highlighted from the perspective of material selection and design for developing biocompatible scaffolds. This review interconnects the advancements made in fundamental materials science research and biomedical technology, and therefore provides scientific insight that is of common interest to the researchers working in different disciplines of healthcare science and technology.

Surface modification of vascular endothelial growth factor-loaded silk fibroin to improve biological performance of ultra-high-molecular-weight polyethylene via promoting angiogenesis

Ultra-high-molecular-weight polyethylene (UHMWPE) has been applied in orthopedics, as the materials of joint prosthesis, artificial ligaments, and sutures due to its advantages such as high tensile strength, good wear resistance, and chemical stability. However, postoperative osteolysis induced by UHMWPE wear particles and poor bone–implant healing interface due to scarcity of osseointegration is a significant problem and should be solved imperatively. In order to enhance its affinity to bone tissue, vascular endothelial growth factor (VEGF) was loaded on the surface of materials, the loading was performed by silk fibroin (SF) coating to achieve a controlled-release delivery. Several techniques including field emission scanning electron microscopy (FESEM) and attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) and water contact angle measurement were used to validate the effectiveness of introduction of SF/VEGF. The result of ELISA demonstrated that the release of VEGF was well maintained up to 4 weeks. The modified UHMWPE was evaluated by both in vitro and in vivo experiments. According to the results of FESEM and cell counting kit-8 (CCK-8) assay, bone marrow mesenchymal stem cells cultured on the UHMWPE coated with SF/VEGF and SF exhibited a better proliferation performance than that of the pristine UHMWPE. The model rabbit of anterior cruciate ligament reconstruction was used to observe the graft–bone healing process in vivo. The results of histological evaluation, microcomputed tomography (micro-CT) analysis, and biomechanical tests performed at 6 and 12 weeks after surgery demonstrated that graft–bone healing could be significantly improved due to the effect of VEGF on angiogenesis, which was loaded on the surface by SF coating. This study showed that the method loading VEGF on UHMWPE by SF coating played an effective role on the biological performance of UHMWPE and displayed a great potential application for anterior cruciate ligament reconstruction.